JPH03131565A - Sintered mullite and production thereof - Google Patents
Sintered mullite and production thereofInfo
- Publication number
- JPH03131565A JPH03131565A JP1267657A JP26765789A JPH03131565A JP H03131565 A JPH03131565 A JP H03131565A JP 1267657 A JP1267657 A JP 1267657A JP 26765789 A JP26765789 A JP 26765789A JP H03131565 A JPH03131565 A JP H03131565A
- Authority
- JP
- Japan
- Prior art keywords
- mullite
- mgo
- weight
- particle size
- raw materials
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 title claims abstract description 85
- 229910052863 mullite Inorganic materials 0.000 title claims abstract description 85
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- 239000002245 particle Substances 0.000 claims abstract description 33
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000000203 mixture Substances 0.000 claims abstract description 23
- 239000002994 raw material Substances 0.000 claims abstract description 22
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 12
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 11
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 claims abstract description 7
- 239000011230 binding agent Substances 0.000 claims abstract description 5
- 239000002734 clay mineral Substances 0.000 claims abstract description 3
- 238000010304 firing Methods 0.000 claims description 4
- 239000004575 stone Substances 0.000 claims description 3
- 238000001238 wet grinding Methods 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 10
- 238000002156 mixing Methods 0.000 abstract description 4
- 238000001035 drying Methods 0.000 abstract description 3
- 229910052681 coesite Inorganic materials 0.000 abstract description 2
- 229910052906 cristobalite Inorganic materials 0.000 abstract description 2
- 235000012239 silicon dioxide Nutrition 0.000 abstract description 2
- 229910052682 stishovite Inorganic materials 0.000 abstract description 2
- 239000000126 substance Substances 0.000 abstract description 2
- 229910052905 tridymite Inorganic materials 0.000 abstract description 2
- 238000013329 compounding Methods 0.000 abstract 1
- 229910052593 corundum Inorganic materials 0.000 abstract 1
- 239000011044 quartzite Substances 0.000 abstract 1
- 229910001845 yogo sapphire Inorganic materials 0.000 abstract 1
- 239000000395 magnesium oxide Substances 0.000 description 21
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 21
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 21
- 239000013078 crystal Substances 0.000 description 11
- 239000000919 ceramic Substances 0.000 description 9
- 239000011521 glass Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 6
- 238000000034 method Methods 0.000 description 6
- 238000000465 moulding Methods 0.000 description 6
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- 239000005995 Aluminium silicate Substances 0.000 description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 description 3
- 235000012211 aluminium silicate Nutrition 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910052878 cordierite Inorganic materials 0.000 description 2
- JSKIRARMQDRGJZ-UHFFFAOYSA-N dimagnesium dioxido-bis[(1-oxido-3-oxo-2,4,6,8,9-pentaoxa-1,3-disila-5,7-dialuminabicyclo[3.3.1]nonan-7-yl)oxy]silane Chemical compound [Mg++].[Mg++].[O-][Si]([O-])(O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2)O[Al]1O[Al]2O[Si](=O)O[Si]([O-])(O1)O2 JSKIRARMQDRGJZ-UHFFFAOYSA-N 0.000 description 2
- 239000003779 heat-resistant material Substances 0.000 description 2
- 230000000704 physical effect Effects 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000011819 refractory material Substances 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 229910052622 kaolinite Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000001272 pressureless sintering Methods 0.000 description 1
- 230000009257 reactivity Effects 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- UONOETXJSWQNOL-UHFFFAOYSA-N tungsten carbide Chemical compound [W+]#[C-] UONOETXJSWQNOL-UHFFFAOYSA-N 0.000 description 1
- 238000004017 vitrification Methods 0.000 description 1
Landscapes
- Compositions Of Oxide Ceramics (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野〕
本発明はムライト質焼結体及びその製造方法に係り、特
に高温強度等の特性に優れ、しかも安価に１是供される
ムライト質焼結体及びその製造方法に関する。[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mullite sintered body and a method for producing the same, and particularly to a mullite sintered body that has excellent properties such as high-temperature strength and can be provided at a low cost. body and its manufacturing method.
［従来の技術］
ムライトはＡＪ２２０３と５ｉ０２からなり、化学組成
は理論的には３Ａｆ１２０＊ ２Ｓ ｉ ０２であり
、その特性としては、耐熱性に優れ、特にクリープ特性
が良好である。また、熱街塁特性は良好であるが電気的
４、ν性はあまり良くない。[Prior Art] Mullite consists of AJ2203 and 5i02, and its chemical composition is theoretically 3Af120*2S i 02, and its properties include excellent heat resistance and particularly good creep properties. Further, although the thermal street rail characteristics are good, the electrical 4,v properties are not so good.
ムライトセラミックスはオールドセラミックスに属し、
その研究の歴史は永く、原料としては、アルミナ源とし
てカオリン、バイヤーアルミナ、シリカ源として珪石が
主に用いられている。最近では、天然ムライトを改質す
ることにより、合成ムライト並の物性を出すことがでと
るようになったが、この研究の主体はムライト組成中の
ＳｉＯ２相の析出及びガラス化の防止であり、原料の調
製や焼結条件などを検討したものである。Mullite ceramics belong to old ceramics.
This research has a long history, and the main raw materials used are kaolin and Bayer alumina as an alumina source, and silica as a silica source. Recently, it has become possible to achieve physical properties comparable to synthetic mullite by modifying natural mullite, but the focus of this research is to prevent the precipitation and vitrification of the SiO2 phase in the mullite composition. The preparation of raw materials and sintering conditions were studied.
一方、ファインセラミックス技術を用いた高純度ムライ
トという理論組成の素材もあり、これは金属アルコキシ
ドから理論組成となるように共沈法で製造したものであ
る。On the other hand, there is also a material with a theoretical composition called high-purity mullite using fine ceramics technology, which is produced by a coprecipitation method from metal alkoxides to a theoretical composition.
しかして、これらの原料を目的に合わせて混合し、焼結
したものかムライト系セラミックス材料といわれ、ムラ
イト系セラミックスはアルミナセラミックスと同様、高
温強度が比較的大きく、天然原料を用いたものは安価な
素材であることから、炉材、サヤ、セッター材、耐熱材
、構造材等、主に耐火材料として用いられてきた。Mullite ceramics are made by mixing and sintering these raw materials according to the purpose, and like alumina ceramics, mullite ceramics have relatively high high-temperature strength, and those made from natural raw materials are inexpensive. Because it is a durable material, it has been mainly used as a refractory material, such as furnace materials, sheaths, setter materials, heat-resistant materials, and structural materials.
［発明が解決しようとする課題］
従来のムライトセラミックスのうち、天然ムライトを改
質したしのでは、長期間の使用や高温使用時に、もとも
と入っているＡＪ２２０３ＳｉＯ２ボンデイングが分解
し、５ｉＯｓ＋がムライト粒界にガラス相として析出す
る。このため、強度が著しく低下し、連続的な使用や繰
り返しの使用に難があワた。[Problems to be solved by the invention] Among conventional mullite ceramics, in the case of modified natural mullite, the AJ2203SiO2 bonding originally contained in it decomposes during long-term use or high-temperature use, and 5iOs+ forms at the mullite grain boundaries. It precipitates as a glass phase. As a result, the strength decreased significantly, making it difficult to use continuously or repeatedly.
アルコシキト法による高純度ムライトは、上記欠点を解
決するために開発されたものであるが、高純度ムライト
は高温強度、耐久性等に大きな改善効果を有するものの
、価格が高いために従来より用いられている耐熱材料等
の工業材料の分野で使用するにはコスト的に不利であっ
た。High-purity mullite produced by the alkoxyquito method was developed to solve the above-mentioned drawbacks, but although high-purity mullite has the effect of greatly improving high-temperature strength and durability, it has not been used conventionally due to its high price. It was disadvantageous in terms of cost for use in the field of industrial materials such as heat-resistant materials.
本発明は上記従来の問題点を解決し、高温強度等の特性
に優れ、かつ安価に提供されるムライト質セラミックス
焼結体及びその製造方法を提供することを目的とする。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a mullite ceramic sintered body that has excellent properties such as high-temperature strength and can be provided at low cost, and a method for manufacturing the same.
［課題を解決するための手段］
請求項（１）のムライト質焼結体は、ＷＣ（炭化タング
ステン）、Ｍｇ０（酸化マグネシウム）及びムライトよ
りなり、ＷＣ，ＭｇＯ含有量がムライトに対して各々３
〜４０重量％、１〜１０重量％であって、ムライト粒径
が１０〜１００μｍであることを特徴とする
請求項（２）のムライト質焼結体の製造方法は、精製粘
土鉱物、バイヤーアルミナ、水酸化アルミニウム及び珪
石よりなる群から選ばれる少なくとも２ｆ！！を主原料
として、ＡＪＺ２０３ ／５ｉ０２の組成比がムライト
生成範囲となるように調合し、該調合原料を９０％以上
が粒径５μｍ以下となるように湿式粉砕した後、粒径５
０μｍ以下のＷＣを前記調合原料に対して３〜４０重量
％、粒径１μｍ以下のＭｇＯを前記調合原料に対して１
〜１０重量％添加混合し、次いで、得られた混合物を乾
燥、解砕し、その後、有機質バインダーを用いて成形し
、成形体を１６００℃以上の温度で１時間以上焼成する
ことを特徴とする。[Means for Solving the Problem] The mullite sintered body of claim (1) is made of WC (tungsten carbide), MgO (magnesium oxide), and mullite, and the WC and MgO contents are each 3% relative to mullite.
40% by weight, 1 to 10% by weight, and the mullite particle size is 10 to 100 μm. , aluminum hydroxide and silica! ! Using AJZ203/5i02 as the main raw material, the composition ratio of AJZ203/5i02 is in the mullite production range, and the blended raw material is wet-pulverized so that 90% or more has a particle size of 5 μm or less.
3 to 40% by weight of WC with a particle size of 0 μm or less based on the raw material, and 1% by weight of MgO with a particle size of 1 μm or less based on the raw material.
It is characterized by adding and mixing ~10% by weight, then drying and crushing the resulting mixture, then molding using an organic binder, and baking the molded product at a temperature of 1600°C or higher for 1 hour or more. .
即ち、本発明は、原料として従来より用いられている安
価な原料を用い、物性改良の手段として、特定のセラミ
ックス粒子を第２相としてムライト結晶内又は粒界面に
分散させることにより高強度化を図り、更に、ＭｇＯの
添加により′ｔｉ離したガラス状シリカを固溶体として
固定し、高純度合成ムライト並の特性を有する材料を提
供するものである。That is, the present invention uses inexpensive raw materials that have been conventionally used as raw materials, and as a means of improving physical properties, high strength is achieved by dispersing specific ceramic particles as a second phase within mullite crystals or at grain boundaries. Furthermore, by adding MgO, the glassy silica separated by 'ti' is fixed as a solid solution, thereby providing a material having properties comparable to that of high-purity synthetic mullite.
以下に本発明の詳細な説明する。The present invention will be explained in detail below.
請求項（１）のムライト質焼結体は、ムライトに対して
３〜４０重量％のＷＣと１〜１０重量％のＭｇＯを含有
するものである。ＷＣの含有量がムライトに対して３重
量％未満では本発明による強度の改善効果が得られず、
４０重量％を超えるとＷＣの量が多くなり過ぎて、ムラ
イト質焼結体としての特性が損なわれる。従って、本発
明においては、ＷＣ含有量はムライトに対して３〜４０
重量％とする。特に、ＷＣ含有量がムライトに対して５
〜２０重量％であると、とりわけ高強度なムライト質焼
結体を得ることができる。The mullite-based sintered body according to claim (1) contains 3 to 40% by weight of WC and 1 to 10% by weight of MgO based on mullite. If the content of WC is less than 3% by weight based on mullite, the strength improvement effect of the present invention cannot be obtained,
If it exceeds 40% by weight, the amount of WC becomes too large and the properties as a mullite sintered body are impaired. Therefore, in the present invention, the WC content is 3 to 40% relative to mullite.
Weight%. In particular, the WC content is 5% compared to mullite.
When the amount is 20% by weight, a particularly high-strength mullite sintered body can be obtained.
一方、ＭｇＯの含有量がムライトに対して１重量％未満
では後述のムライト生成時に遊離するガラス相を十分に
固定することかできず、強度改善効果が十分ではなく、
１０重量％を超えるとＭｇＯ相が大きくなり好ましくな
い。従って、本発明においては、ＭｇＯ含有量はムライ
トに対して１〜１０重量％とする。特に、ＭｇＯ含有量
がムライトに対して２〜５重二重量あると、とりわけ高
強度なムライト質焼結体を得ることができる。On the other hand, if the MgO content is less than 1% by weight based on mullite, the glass phase released during mullite formation, which will be described later, cannot be sufficiently fixed, and the strength improvement effect is not sufficient.
If it exceeds 10% by weight, the MgO phase becomes large, which is not preferable. Therefore, in the present invention, the MgO content is 1 to 10% by weight based on mullite. In particular, when the MgO content is 2 to 5 times the amount of mullite, a particularly high-strength mullite-based sintered body can be obtained.
請求項（１）のムライト質焼結体中のムライト結晶は、
粒径が１００μｍの範囲のものである。The mullite crystal in the mullite sintered body of claim (1) is
The particle size is in the range of 100 μm.
ムライト結晶の粒径が１００μｍよりも犬ぎいと得られ
るムライト質焼結体の曲げ強度が低下し、また１０μｍ
よりも小さいとＷＣ粒子やＭｇＯ粒子をムライト結晶内
又は粒界面に取り込み難くなる。従って、ムライト結晶
の粒径は１０〜１００μｍ、好ましくは１０〜５０μｍ
とする。When the grain size of mullite crystals is smaller than 100 μm, the bending strength of the resulting mullite sintered body decreases;
If it is smaller than this, it becomes difficult to incorporate WC particles and MgO particles into mullite crystals or grain boundaries. Therefore, the grain size of mullite crystals is 10 to 100 μm, preferably 10 to 50 μm.
shall be.
一方、ムライト結晶又は粒界面に取り込まれてムライト
質焼結体内に含有されているＷＣ粒子の粒径が微細過ぎ
ると表面活性が生じ、ＷＣ自身の表面酸化が起きる。ま
た、ムライトと均一に混合することが難しい。逆にＷＣ
粒子の粒径が大き過ぎるとムライト結晶粒界にのみＷＣ
が存在するようになり、粒界クラック発生の原因となる
。従フて、本発明において、ＷＣ粒子の粒径は５０μｍ
以下、特に１０μｍ以下、とりわけ３〜１０μｍである
ことが好ましい。On the other hand, if the particle size of the WC particles incorporated into the mullite crystals or grain boundaries and contained in the mullite sintered body is too fine, surface activity will occur and the surface oxidation of the WC itself will occur. It is also difficult to mix uniformly with mullite. On the contrary, WC
If the particle size is too large, WC will form only at the mullite grain boundaries.
comes to exist, causing grain boundary cracks to occur. Therefore, in the present invention, the particle size of the WC particles is 50 μm.
Below, it is especially preferable that it is 10 micrometers or less, especially 3-10 micrometers.
また、ＭｇＯ粒子の粒径は、大きいと５ｉ０２との反応
性に劣ることから、１μｍ以下、好ましくは０．５μｍ
以下とする。In addition, the particle size of the MgO particles is 1 μm or less, preferably 0.5 μm, since the reactivity with 5i02 is poor if the size is large.
The following shall apply.
なお、ムライト質焼結体中のムライトはその組成が理論
組成のＡ ｉ２０３／ Ｓ ｉ Ｏ２＝３／２（モル比
） 即ち７１．８／２８．２（重量％）であることが好
ましい。ムライト組成のＡＩＬ２０ｇが理論組成よりも
多過ぎるとＡｊ２＋＋ ０３中にムライト結晶が分散し
た形となり十分な強度が得られない。逆に、ムライト組
成の５ｉ０２が理論組成よりも多過ぎると、ムライト中
に遊離シリカ相がガラス相となって生成し、十分な高温
強度が得られない、従って、ムライト質焼結体中のムラ
イトは、理論組成Ａｊ２２０３ ／Ｓ ｉ Ｏ２＝ ３
／ ２ （モル比）にできるだけ近い組成であること
が好ましい。The mullite in the mullite-based sintered body preferably has a theoretical composition of A i203/S i O2=3/2 (molar ratio), that is, 71.8/28.2 (wt%). If 20 g of AIL of mullite composition is too much than the theoretical composition, mullite crystals will be dispersed in Aj2++03 and sufficient strength will not be obtained. On the other hand, if the mullite composition contains too much 5i02 than the theoretical composition, the free silica phase will form in the mullite as a glass phase, and sufficient high-temperature strength will not be obtained. is the theoretical composition Aj2203 /S i O2= 3
It is preferable that the composition be as close as possible to /2 (molar ratio).
以上のように、可能な限りシリカガラス相が析出しない
ようにしても、若干の析出があり、このため十分に強度
を上げることはできない。ここにＭｇＯを添加した場合
、ムライト生成時に遊離する若干のシリカガラスが、゛
このＭｇＯと反応して固定されるため、ムライト粒界に
ガラス相として析出しなくなり、高強度なものとなる。As described above, even if the silica glass phase is prevented from precipitating as much as possible, some precipitation still occurs, and therefore the strength cannot be sufficiently increased. When MgO is added here, some silica glass liberated during mullite formation reacts with this MgO and is fixed, so it does not precipitate as a glass phase at the mullite grain boundaries, resulting in high strength.
ＭｇＯの添加量を１〜１０重量％、より好ましくは２〜
５重量％とすると、近因ガラス相は、コージライトとし
て固定されているものと思われ、Ｘ線回折では含有量が
少ないため確認できないが、非常に高強度なものとなっ
た。なお、前述の如く、Ｍｌ（０の添加量が多すぎると
ＭｇＯ相が大きくなり好ましくない。また、少なすぎる
と遊離ガラス相を十分固定できなくなり効果がない。The amount of MgO added is 1 to 10% by weight, more preferably 2 to 10% by weight.
When the content was 5% by weight, the proximate glass phase was thought to be fixed as cordierite, and although it could not be confirmed by X-ray diffraction due to the small content, it became extremely strong. As mentioned above, if the amount of Ml(0) added is too large, the MgO phase will become large, which is undesirable. If it is too small, the free glass phase cannot be fixed sufficiently, so there is no effect.
このような請求項（１）のムライト質焼結体は請求項（
２）の方法により容易かつ効率的に低コストにて製造す
ることができる。Such a mullite sintered body of claim (1) is
By the method 2), it can be manufactured easily and efficiently at low cost.
以下に請求項（２）のムライト質焼結体の製造方法につ
いて説明する。The method for producing a mullite sintered body according to claim (2) will be explained below.
請求項（２）の方法においては、まず、原料として精製
粘土鉱物、バイヤーアルミナ、水酸化アルミニウム又は
珪石（シリカ）を用い、Ａ ｆｌ ２０ ｚ ／ Ｓ
ｉ Ｏ２組成比がムライト生成範囲、好ましくはＡ ｊ
２２０ ｓ ／ Ｓ ｉ Ｏ２＝ ３ ／ ２（モル比
）となるように調合する。この場合、特に原料としては
精製カオリンとバイヤーアルミナ又は水酸化アルミニウ
ム、或いは、バイヤーアルミナ又は水酸化アルミニウム
と珪石を用いるのが好ましい。これらの原料はその所要
量をボールミル、又はアトライター等によりアルコール
等を用いて９０％以上が粒径５μｍ以下となるように湿
式粉砕する。次に、得られた粉砕物に粒径５０μｍ以下
、好ましくは１０μｍ以下、特に３〜１０μｍのＷＣを
該粉砕物に対して３〜４０重量％、好ましくは５〜２０
重量％添加し、更に１μｍ以下のＭｇＯを１〜１０重量
％、好ましくは２〜５重量％添加しボールミル等で混合
する。In the method of claim (2), first, refined clay minerals, Bayer alumina, aluminum hydroxide, or silica are used as raw materials, and A fl 20 z / S
i O2 composition ratio is within the mullite formation range, preferably A j
220 s/S i O2 = 3/2 (molar ratio). In this case, it is particularly preferable to use purified kaolin and Bayer alumina or aluminum hydroxide, or Bayer alumina or aluminum hydroxide and silica stone as raw materials. The required amount of these raw materials is wet-milled using alcohol or the like using a ball mill or attritor so that 90% or more of the powder has a particle size of 5 μm or less. Next, WC having a particle size of 50 μm or less, preferably 10 μm or less, particularly 3 to 10 μm is added to the obtained pulverized material in an amount of 3 to 40% by weight, preferably 5 to 20% by weight based on the pulverized material.
% by weight is added, and further 1 to 10 weight %, preferably 2 to 5 weight % of MgO having a diameter of 1 μm or less is added and mixed using a ball mill or the like.
得られた混合物は乾燥、解砕した後、ポリビニルアルコ
ール（ＰＶＡ）等の有機質バインダーを用いて成形する
。成形は３００ ｋ ｇ ｆ ／ ｃ ｍ”以上での加
圧成形後、ｔ ＯＯＯｋ ｇ ｆ ／ ｃ ｒｎ’以上
での静水圧プレス成形による２段成形で行なうのが好ま
しい。The resulting mixture is dried, crushed, and then molded using an organic binder such as polyvinyl alcohol (PVA). It is preferable that the molding is carried out in two steps, including pressure molding at 300 kg f/cm'' or higher, followed by isostatic press molding at t OOOkg f/c rn' or higher.
得られた成形体はホットプレス又は常圧焼結により焼成
し、ムライト質焼結体を得る。この場合、昇温速度は５
０〜ｂ
好ましく、焼成温度は１６００℃以上、好ましくは１６
００〜１６５０℃とし、焼成時間は１時間以上、好まし
くは１〜３時間とするのが好ましい。なお、ホットプレ
スを採用する場合、圧力は３００〜６００ ｋ ｇ ／
ｃ ｒｒ１″程度とするのが好ましい。The obtained molded body is fired by hot pressing or pressureless sintering to obtain a mullite sintered body. In this case, the heating rate is 5
0 to b Preferably, the firing temperature is 1600°C or higher, preferably 16
It is preferable that the temperature is 00 to 1650°C and the firing time is 1 hour or more, preferably 1 to 3 hours. In addition, when using a hot press, the pressure is 300 to 600 kg/
It is preferable to set it to approximately 1″.
［作用］
一般に、精製カオリン、バイヤーアルミナ、水酸化アル
ミニウム又は珪石等の原料を用いて、これをボールミル
等で微粉砕して混合しても、原子レベルで理論組成に混
合することは不可能であり、焼結により拡散させるため
には長時間を必要とする。[Function] In general, even if raw materials such as refined kaolin, Bayer alumina, aluminum hydroxide, or silica stone are used and mixed by finely pulverizing them with a ball mill, etc., it is impossible to mix them to the theoretical composition at the atomic level. However, it takes a long time to diffuse through sintering.
これに対して、ムライト組成中に第２相としてＷＣ粒子
を３〜４０重量％、ＭｇＯ粒子を１〜１０重量％添加す
ると、ボールミル等による粉砕混合でも、通常の成形、
焼成により高温強度に優れたムライト質焼結体が得られ
る。On the other hand, if 3 to 40% by weight of WC particles and 1 to 10% by weight of MgO particles are added as a second phase to the mullite composition, normal molding and mixing with a ball mill etc.
By firing, a mullite sintered body with excellent high-temperature strength is obtained.
本発明において、ＷＣ添加による高温強度改善の機構の
詳細は明らかではないが、ムライト結晶内又は粒界面に
取り込まれたＷＣ粒子がムライト中の５ｉ０２のガラス
相への８動をブロックしているため、更には、ＷＣ粒子
がムライト結晶粒内や結晶粒界へ分散し、ムライト結晶
の成長を抑制しているためと考えられる。また、ＭｇＯ
添加については、遊離シリカ（ガラス相）がＭｇＯと反
応してコージライトなどの結晶となり、固定されるため
、ガラス相の析出がなくなり、高温強度の大きなものと
なっているためと考えられる。In the present invention, although the details of the mechanism of high-temperature strength improvement due to WC addition are not clear, it is because WC particles incorporated into mullite crystals or at grain boundaries block the movement of 5i02 into the glass phase in mullite. Furthermore, this is considered to be because the WC particles are dispersed within the mullite crystal grains and at the grain boundaries, suppressing the growth of the mullite crystals. Also, MgO
Regarding the addition, it is thought that free silica (glass phase) reacts with MgO to form crystals such as cordierite and is fixed, thereby eliminating precipitation of the glass phase and resulting in high high-temperature strength.
［実施例コ
以下に実施例及び比較例を挙げて本発明をより具体的に
説明する。[Example] The present invention will be described in more detail with reference to Examples and Comparative Examples below.
実施例１，２、比較例１
精製したカオリナイトに組成がＡｆ１２０３ ／５ｉＯ
２＝３／２（モル比）となるようにアルミナを添加し、
ボールミル（Ｚｒ０２ボール）によりアルコールを用い
て４８時時間式粉砕した。なお、この場合、メディア攪
拌型粉砕１（アトライター）を用いると１〜２時間で処
理することが可能である。原料を９０％以上が粒径５μ
ｍ以下となるように粉砕した後、これにＷＣ粉末（日本
新金属社製：平均粒径５μｍ）及びＭｇ○粉末（三菱鉱
業セメント■製：平均粒径０．５μｍ）を第１表に示す
量添加しく比較例１は添加せず）、更にボールミルで５
時間混合した。これを乾燥、解砕した後、有機質バイン
ダー（ＰＶＡ）を５重量％添加して十分に混練した。Examples 1 and 2, Comparative Example 1 Purified kaolinite with composition Af1203/5iO
Add alumina so that 2 = 3/2 (mole ratio),
It was milled for 48 hours using alcohol in a ball mill (Zr02 ball). In this case, if the media agitation type pulverization 1 (attritor) is used, the treatment can be completed in 1 to 2 hours. More than 90% of raw materials have a particle size of 5μ
After pulverizing the powder to a particle size of less than m, WC powder (manufactured by Japan Shinkinzoku Co., Ltd.: average particle size 5 μm) and Mg○ powder (manufactured by Mitsubishi Mining Cement ■: average particle size 0.5 μm) are added to it as shown in Table 1. (in Comparative Example 1, it was not added), and further in a ball mill,
Mixed for an hour. After drying and crushing this, 5% by weight of an organic binder (PVA) was added and thoroughly kneaded.
混練物をプレス成形により５０ｍｍφＸ５ｍｍに５００
ｋ ｇ ／ ｃ ｒｎ’で成形した後、ラバープレス
により１５００ｋｇ／ｃｒｎ”で更に加圧して成形体を
得た。この成形体を焼結してムライト質焼結体を得た。The kneaded material was press-molded into a size of 50 mmφ x 5 mm.
After molding at a pressure of 1,500 kg/crn', a rubber press was used to further press the molded product at 1,500 kg/crn' to obtain a molded body. This molded body was sintered to obtain a mullite sintered body.
なお、焼結はホットプレスを用い、昇温速度は１５０℃
／ ｈ ｒとし、３００ ｋ ｇ ／ ｃ ｒｎ’にて
１６００℃で１時間行なった。Note that sintering uses a hot press, and the temperature increase rate is 150°C.
/ hr, and 300 kg/crn' and 1600° C. for 1 hour.
得られたムライト質焼結体の計時性を第１表に示す。Table 1 shows the timekeeping properties of the obtained mullite sintered body.
溝）
表
第１表より所定量のＷＣ及びＭｇＯを添加したムライト
質焼結体により、常温から１３００℃といった高温まで
安定して著しく高い強度が得られることが明らかである
。Groove) From Table 1, it is clear that the mullite sintered body to which predetermined amounts of WC and MgO are added can stably provide extremely high strength from room temperature to high temperatures such as 1300°C.
［発明の効果コ
以上詳述した通り、本発明のムライト質焼結体は、安価
な原料を用いて低コストに提供されるものであり、しか
も、高温強度、耐久性等の特性に著しく優れる。従って
、本発明のムライト質焼結体は、工業用耐火材料等とし
て、長期にわたり極めて有効に使用することがで仕る。[Effects of the Invention] As detailed above, the mullite sintered body of the present invention is provided at low cost using inexpensive raw materials, and moreover, it has outstanding properties such as high-temperature strength and durability. . Therefore, the mullite sintered body of the present invention can be used extremely effectively over a long period of time as an industrial refractory material.
しかして、このような本発明のムライト質焼４６体は、
本発明の方法により容易かつ効率的に低コストにて製造
することが可能とされる。Therefore, the 46 mullite fired bodies of the present invention are as follows:
The method of the present invention makes it possible to manufacture easily and efficiently at low cost.
Claims (2)
がムライトに対して３〜４０重量％、ＭｇＯ含有量がム
ライトに対して１〜１０重量％であって、ムライト粒径
が１０〜１００μｍであることを特徴とするムライト質
焼結体。(1) Consists of WC, MgO and mullite, with a WC content of 3 to 40% by weight based on mullite, an MgO content of 1 to 10% by weight based on mullite, and a mullite particle size of 10 to 100 μm. A mullite sintered body characterized by:
ニウム及び珪石よりなる群から選ばれる少なくとも２種
を主原料として、Ａｌ＿２Ｏ＿３／ＳｉＯ＿２の組成比
がムライト生成範囲となるように調合し、該調合原料を
９０％以上が粒径５μｍ以下となるように湿式粉砕した
後、粒径５０μｍ以下のＷＣを前記調合原料に対して３
〜４０重量％、粒径１μｍ以下のＭｇＯを前記調合原料
に対して１〜１０重量％添加混合し、次いで、得られた
混合物を乾燥、解砕し、その後、有機質バインダーを用
いて成形し、成形体を１６００℃以上の温度で１時間以
上焼成することを特徴とするムライト質焼結体の製造方
法。(2) At least two selected from the group consisting of purified clay minerals, Bayer alumina, aluminum hydroxide, and silica stone are blended as main raw materials so that the composition ratio of Al_2O_3/SiO_2 falls within the mullite production range, and the blended raw materials are After wet grinding so that 90% or more has a particle size of 5 μm or less, WC with a particle size of 50 μm or less is
~40% by weight of MgO with a particle size of 1 μm or less is added and mixed in an amount of 1 to 10% by weight with respect to the above-mentioned blended raw materials, then the resulting mixture is dried and crushed, and then molded using an organic binder, A method for producing a mullite sintered body, which comprises firing the molded body at a temperature of 1600° C. or higher for 1 hour or more.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1267657A JPH03131565A (en) | 1989-10-13 | 1989-10-13 | Sintered mullite and production thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1267657A JPH03131565A (en) | 1989-10-13 | 1989-10-13 | Sintered mullite and production thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH03131565A true JPH03131565A (en) | 1991-06-05 |
Family
ID=17447725
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1267657A Pending JPH03131565A (en) | 1989-10-13 | 1989-10-13 | Sintered mullite and production thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH03131565A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107266097A (en) * | 2017-07-28 | 2017-10-20 | 武汉科技大学 | A kind of light weight mullite refractory and preparation method thereof |
| CN114853487A (en) * | 2022-05-06 | 2022-08-05 | 苏州诺瑞达新材料科技有限公司 | Mullite castable based on titanium carbide and tungsten carbide composite |
-
1989
- 1989-10-13 JP JP1267657A patent/JPH03131565A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107266097A (en) * | 2017-07-28 | 2017-10-20 | 武汉科技大学 | A kind of light weight mullite refractory and preparation method thereof |
| CN114853487A (en) * | 2022-05-06 | 2022-08-05 | 苏州诺瑞达新材料科技有限公司 | Mullite castable based on titanium carbide and tungsten carbide composite |
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